Abstract

In the study of the mechanism of non-specific permanentadhesion of bacteria at the solid-liquid interface a numberof alternative approaches have been used. These include;the use of thermodynamic models, to explain observations ofbiocontact phenomenal the use of disruptive chemicals, enzymes and electronnicroscopy to investigate the nature of the adhesive bond and finally the biochemical analysis of cell surface components possibly involved in the process. In this study all three approaches were combined in an investigation of the role of cell surface components on the attachment of freshwater organisms to solid surfaces. A thermodynamic relationship was found using attachment assays on a number of freshwater isolates emphasising the influence of water on the adhesive process. Further investigations of phenotypic changes in membrane surface composition of a number of Pseudomonas isolates using continuous culture demonstrated the involvement of polysaccharide in the inhibition of adhesion. A number of adhesion mutants were analysed for genotypic changes in outer membrane proteins, lipopolysaccharides and exopolysaccharides which also confirmed the inhibitory role of polysaccharides. The results demonstrate the role of cell surface characteristics in the adaptability of the organism to micro-environments such as a solid/liquid or air/liquid interface or the aqueous phase.